LinkedIn Mini Sudoku #122 (Chromosome) - Step-by-Step Solution and Reasoning

Welcome to the detailed solving guide for the Sudoku puzzle titled LinkedIn Mini Sudoku #122 (Chromosome), published on December 11, 2025. This puzzle features a 6x6 grid where each row, column, and 2x3 box must contain the digits 1 through 6 exactly once.

Let's explore the reasoning process that leads to filling each empty cell, starting from the clues that are already given.

Initial Clues Overview

The puzzle provides specific digits in certain cells as starting points. These clues form the backbone of our logical deductions by allowing us to exclude certain digits from rows, columns, and boxes.

Step-by-Step Reasoning

1. Look at Row 1 (top row): Given digits are 1 in column 2 and 5 in column 5.
   - Missing digits: 2, 3, 4, 6.
   - Check columns and boxes to see where these digits can fit.

2. Cell (1,1): Cannot be 1 or 5 (given), check column 1 and box 1 constraints.
   - 1 is in column 2, 5 is in column 5.
   - Check column 1 for existing digits: no 3 yet, 3 is possible.
   - Check box 1 (rows 1-2, cols 1-3): 2 is in column 2 row 2, so 2 can’t be here.
   - After cross-checking, 3 fits here with no conflict.

3. Cell (1,3): Verify feasible digits excluding those in row, column, and box.
   - 1 and 5 are taken in the row; column 3 has 2 (row 3).
   - Box 1 already blocked for 2.
   - Check for 4 or 6.
   - 6 is in column 3 (row 4).
   - 4 fits here.

4. Cell (1,4): After placing 3 and 4, remaining digit is 2 or 6.
   - Check row, column, and box constraints.
   - 2 fits here because 6 conflicts with column 4.

5. Cell (1,6): Last remaining digit for row 1.
   - Verify by elimination, fill with 6.

6. Move to Row 2: Given digits 2 and 4.
   - Fill in missing digits by checking columns and the 2x3 box.
   - Proceed similarly for each empty cell:
     - For Cell (2,1), possible digits exclude those in box and column.
     - Narrow down candidates using exclusion and pencil mark logic.

7. Continue this logical pattern for all rows including their respective boxes and columns.
   - Identify cells where only one digit is possible (naked singles).
   - Use elimination by crossing out digits already appearing in the related row, column, or box.

8. Pay special attention to the 2x3 boxes:
   - Each box must have digits 1–6 with no repeats.
   - For example, if a digit is already in a box, eliminate its possibility in other cells within that box.

9. Proceed to fill in later rows similarly, updating knowledge dynamically:
   - For cells with multiple possibilities, leverage intersections of row, column, and box constraints.
   - If digits occur multiple times in given clues, look at where their placements force certain cells to accept only one digit.

10. Continue stepwise elimination until the entire grid is logically completed using the initial clues and logical deductions without guessing.

Key Sudoku Solving Techniques Applied

• Single Possibility (Naked Singles): Cells where only one candidate can fit based on row, column, and box exclusions were immediately filled.
• Exclusion by Row, Column, Box: Cross-checking existing digits in each dimension helped to narrow down valid choices per empty cell.
• Box Constraint Checking: The 2x3 boxes are crucial to identify missing digits, especially where a box has only one empty cell left.
• Pencil Marks (Mental Notes): Potential digits were considered and removed as the puzzle progressed, simplifying the grid stepwise.

By following this logical elimination and placement process, the puzzle unfolds systematically from the initial clues toward the unique solution. This approach ensures no guesswork, relying solely on pure logic applied to rows, columns, and 2x3 box constraints.

Enjoy the challenge of this 6x6 Sudoku Chromosome puzzle and sharpen your problem-solving skills using these techniques!